(Beyond Pesticides, January 4, 2011) A report released by the Environmental Working Group (EWG) finds that drinking water in 31 cities across the country is contaminated with hexavalent chromium, or chromium-6, a carcinogenic chemical contaminant with numerous sources including treated wood utility poles that line streets and backyards across the the United States. Wood treated with chromated copper arsenate (CCA), such as playgrounds, decks, and railroad ties, in addition to utility poles, can leach the chemicals into soils and groundwater, creating serious risks to public health. Other common sources of chromium-6 pollution include discharge from steel and pulp mills as well as metal-plating and leather-tanning facilities. It can also pollute water through erosion of natural deposits.

The use of CCA in the treatment of utility poles is notable not only because of the presence of poles in numerous communities throughout the country, but also because utility companies often donate or sell decommissioned poles, which are then used by homeowners to line walkways and gardens or create structures around the yard, unknowingly contributing to the proliferation of these toxic substances. Beyond Pesticides has worked on the issue of wood treatments, including CCA, since the mid-1980s and has advocated for the adoption of alternative treatments and materials by utility companies. The use of alternative materials, such as recycled steel or concrete, eliminates the need to use toxic preservatives such as CCA, dramatically reducing the risk of chemical contamination to local communities. Read our program page on wood preservatives to learn more about these chemicals and how you can take action to help eliminate them.

Despite mounting evidence of the toxic effects of chromium-6, the U.S. Environmental Protection Agency (EPA) has not set a legal limit for the contaminant in tap water and does not require water utilities to test for it. However, shortly after the release of the EWG report, EPA announced that it will work with local communities address the levels of chromium-6 in their water. The agency is also currently in the process of reviewing its approach to chromium and is deciding whether or not to set a specific limit on chromium-6. Currently, the limits only apply to “total chromium,” which includes trivalent chromium, an essential nutrient for human metabolism, in addition to the toxic hexavalent form.

The authoritative National Toxicology Program (NTP) of the U.S. Department of Health and Human Services has said that chromium-6 in drinking water shows “clear evidence of carcinogenic activity” in laboratory animals, increasing the risk of gastrointestinal tumors. Just last October, a draft review by the EPA similarly found that ingesting the chemical in tap water is “likely to be carcinogenic to humans.” Other health risks associated with exposure include liver and kidney damage, anemia and ulcers.

In response to the NTP study and others, California last year became the first state to propose setting a public health goal for chromium-6 in drinking water of 0.06 parts per billion (ppb) — setting the stage for establishing a statewide enforceable limit.

The hazards of chromium-6 contamination first came to light in 1993, when Erin Brockovich helped build a now-famous class action lawsuit against Pacific Gas and Electric Co. (PG&E) for polluting the water supply of Hinkley, Calif. The suit eventually led to a $333 million settlement.

“Every single day, pregnant mothers in Norman, Oklahoma, school children in Madison, Wisconsin, and many other Americans are drinking water laced with this cancer-causing chemical,” said EWG senior scientist Rebecca Sutton, Ph.D. “If the EPA required local water utilities to test for hexavalent chromium, the public would at least know if it was present in their local water. Without mandatory tests and a safe legal limit that all utilities must meet, many of us will continue to swallow some quantity of this carcinogen every day.”

“It is sometimes difficult to understand why I still have to warn the public about the presence of hexavalent chromium in drinking water 23 years after my colleagues and I first sounded the alarm,” said Ms. Brockovich. “This report underscores, in fairly stark terms, the health risks that millions of Americans still face because of water contamination.”

In 25 cities tested by EWG, concentrations of chromium-6 in tap water were higher than California’s proposed public health limit. In Norman, Okla. (population 90,000), the level was more than 200 times the state’s proposed safe level.

The 31 cities shown to have chromium-polluted tap water draw from utilities that collectively serve more than 26 million people. In California, the only state that requires testing for chromium-6, utilities have reported detecting the compound in tap water supplied to more than 31 million people, according to an EWG analysis of data from the state water agency.

Concerned consumers can dramatically reduce the amount of the chemical in their drinking water by investing in a reverse osmosis filtration system for the home. There is no legal limit for hexavalent chromium in bottled water either, so consumers cannot assume it is free of the contaminant.

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on Tuesday, January 4th, 2011 at 12:01 am and is filed under California, Cancer, CCA, Water, Wood Preservatives.
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